Wireless communications systems typically make use of a plurality of wireless carrier frequencies that have been assigned to each system by an appropriate regulatory authority. Although guidelines for making these assignments generally attempt to minimize the possibility of interference among nearby systems, they do not preclude such interference. In particular, when systems using adjacent or offset carrier frequencies have overlapping coverage areas, there is a potential for interference. For example, consider a communication unit of a first system located near a base site of a second system, and operating on a frequency adjacent to a frequency used by the base site. The base site may receive strong signal level transmissions from the communication unit which may interfere with weaker signals being received by the base site from distantly located communication units of the second system. The type of interference is known in the art as the "near-far" interference problem.
Previous solutions have been proposed to minimize such interference problems. Newer systems, however, and in particular, digital systems with time division multiplexing, present challenges against which the previous solutions are inadequate.
Accordingly, a need exists for a way to better prevent interference on wireless carrier frequencies, particularly with respect to adjacent wireless carrier frequencies used by independent communication systems.